GB2254013A - Waste outlet filter - Google Patents

Abstract

A rigid tubular filter element 2 is located in a separate housing 4 or directly in the drainage outlet pipe from a urinal bowl 7, sink, basin or mortuary table. The element has an upper flange round its open mouth and is otherwise perforated all over. The flange may have larger perforations to bypass the liquid if the element fills with debris. The perforations may be punched out, leaving burrs which project downwards to restrain the element against lateral movement, or separate lugs may do this. <IMAGE>

Description

FILTER AND FILTER UNIT This invention relates to a filter and a filter unit for location between a drainage outlet from, for example, a urinal, sink, basin or mortuary table, or like fitting, and downstream pipework. The invention extends to an assembly comprising a filter and/or a filter unit.

In accordance with a first aspect of the present invention, there is provided a filter for location beneath a drainage outlet, the filter comprising a hollow filter body which includes a filter surface, wherein a first end of the filter is arranged to be located beneath the drainage outlet, the filter including a mouth open to the first end which mouth is arranged, in use, to allow liquid to pass from the drainage outlet into the hollow body so that the liquid may be filtered by the filter surface.

Preferably, the periphery of the filter body is defined, at least in part, by said filter surface.

Preferably, the filter body is defined substantially wholly by said filter surface.

The filter may have a flange at the first end, about the mouth. The flange may have a plurality of apertures, so that liquid may pass through the apertures, as well as through the filter surface of said filter body.

The filter is preferably arranged to be fitted in a waste down pipe beneath a drainage outlet. Preferably, the filter includes positioning means for positioning the filter in the waste down pipe. The positioning means is preferably arranged such that, with the filter fitted in a waste down pipe, there is a gap defined between the outer periphery of the hollow filter body and the down pipe. Preferably, in an assembly comprising a filter and a down pipe, a gap is defined between the down pipe and the entire outer periphery of the filter body.

Where the filter includes a flange as described above, the positioning means preferably comprises a projecting part or parts on said flange. Preferably, the projecting part or parts is/are disposed inwardly of an outside edge of said flange. The projecting part or parts is/are preferably arranged to restrict transverse movement of the filter, in use, for example, when disposed beneath a drainage outlet in a waste down pipe. The projecting part or parts is/are preferably provided on a surface of the flange which surface is a lowermost surface in use.

Preferably, a plurality, more preferably three, projecting parts are provided. The projecting part(s) may be in the form of pins. Alternatively, the projecting part(s) may comprise burred edges of holes punched (or otherwise formed) in the flange.

Preferably, the hollow filter body is circularly cylindrical and is arranged with the cylindrical axis upright in use. Preferably, the diameter of the filter body is in the range 35mm to 90mm. In a preferred embodiment, the filter body has a diameter of less than 50mm.

Preferably, the flange, when provided, is ringshaped. The diameter of the flange (measured to the outside edge thereof) is preferably greater than 50mm, more preferably greater than 70mm. It will be appreciated, that, in any case, the diameter of the ring-shaped flange is suitably greater than that of the filter body.

Suitably, the filter is elongate, its length exceeding its mean width, suitably by a factor of at least 2. Preferably, the filter is at least 150mm long; more preferably it is at least 200mm long.

The filter surface preferably extends from the mouth of the filter towards a second end of the filter. The filter surface may suitably be of woven mesh material, or perforate construction. Preferably, liquid may flow through the filter surface at any position beneath the first end. Thus, liquid may flow through higher regions of the filter surface, should solid materials block lower regions.

Preferably, the filter is constructed of a generally rigid material which is resistant to corrosion. Suitable material may include stainless steel and plastics.

Preferably, a surface of the filter is highly polished and/or has a mirror finish. The filter may be coated with a material which is resistant to build up of chemical deposits such as alkaline or acidic deposits, for example, deposits of uric acid, or may be made of such resistant material, for example, a said plastics material.

The invention extends to an assembly comprising a filter as described in any statement herein, the filter being secured in a down pipe beneath a drainage outlet.

The invention extends to the use of a filter as described in any statement herein for filtering liquid passing from a drainage outlet of a fitting, for example, a urinal, sink, basin or mortuary table.

The invention further extends to a filter unit for location beneath a drainage outlet, the unit comprising a first end for location adjacent a said drainage outlet, and a second end for connection to downstream pipework, the unit comprising a filter as described in any statement herein wherein the filter has its mouth open to the first end, the unit further comprising a housing within which the filter is received, with a gap being defined between the housing and the filter, the housing having an outlet at the second end, for connection to downstream pipework.

Preferably the housing is made of a generally rigid material which is resistant to corrosion. Suitable materials for the housing include stainless steel and plastics.

Preferably a surface of the housing is highly polished and/or has a mirror finish. The housing may be coated with a material which is resistant to build up of chemical deposits such as alkaline or acidic deposits, for example deposits of uric acid, or may be made of such resistant material, for example, a said plastics material.

The housing may suitably be of complimentary shape to the filter. Thus, if the filter is cylindrical, the housing may suitably also be cylindrical. Suitably, the gap between the housing and filter extends around the entire filter surface. The housing may be adapted for securement about a said drainage outlet. The wall of the housing at the second end (the bottom wall in use) is suitably removable, to aid the securement of downstream pipework.

The invention extends to the use of a filter unit as described in any statement herein for filtering liquid passing from a drainage outlet of a fitting, for example, a urinal, sink, basin or mortuary table.

The filter and/or filter unit of the present invention may be used in relation to fittings such as urinals, sinks, basins, shower trays, and in relation to mortuary tables. The filter unit may be a particular benefit when used in relation to a fitting in which the outlet is above the floor. Such fittings tend to have relatively narrow downstream pipework, and the filter unit of the present invention removes constraints on filter size - for example, it may desirably be of larger transverse cross-sectional area than that of the downstream pipework.

In a filter unit for use at the drainage outlet of a sink or basin, a removable plug may be provided, for sealing location over the mouth of the filter.

In accordance with a further aspect of the present invention, there is provided an assembly of a fitting, for example a urinal, basin, sink, or mortuary table, having a drainage outlet; and a filter unit as described above fitted beneath the drainage outlet; and downstream pipework connected to the lower end of the filter unit.

Suitably, the transverse cross-sectional area of the filter exceeds the transverse cross-sectional area of the downstream pipework.

The invention will now be further described, by way of example, with reference to the accompanying drawings in which : Figure 1 shows, in cross-section, a filter unit attached beneath the drainage outlet of a bowl urinal; Figure 2 shows the filter of the type shown in Figure 1, in perspective view; Figure 3 shows, in perspective view partly broken away, an alternative embodiment of filter unit, for location beneath the drainage outlet of a wall hung urinal; Figure 4 shows, in cross-sectional view, a filter unit located beneath the drainage outlet of a sink; Figure 5 shows, in perspective view partly in crosssection, a filter; Figure 6 is a top plan view of the filter of Figure 5; and Figure 7 is a side elevation, partly broken away, of a filter in a waste down pipe.

With reference to Figures 1 and 2, the filter unit comprises a filter 2 located in a housing 4. The filter unit is located beneath the drainage outlet 6 of a bowl urinal 7.

The filter 2 is elongate in shape, being formed as a cylinder, and arranged with its axis vertical. At its upper end it has a mouth 8 open to the drainage outlet 6, and around the mouth is an annular flange 10. The periphery of the flange 10 rests on a seating 9 formed at the outlet 6 of the bowl urinal. The flange 10 has a circular array of circular apertures 12 as seen in Figure 2.

Both the side wall and the lower end wall 14 of the filter 2 are perforate, being formed with a very large number of pinhole apertures.

The housing 4 is also cylindrical in shape. It is longer and is of greater diameter than the filter 2, so that there is a gap at all places therebetween. The housing is secured, at its upper end, to the lower region of the bowl urinal. In this embodiment the bowl urinal is of stainless steel and securement is by means of screws passing through tapped holes in the bowl urinal, and being secured in nuts 16 which are welded to the housing.

The bottom wall 18 of the housing has an outlet, and is there secured to downstream pipework 20. To aid the securement of the pipework to the housing, the bottom wall 18 of the housing is removable. It is securable to the housing by means of screws 22 engaging nuts 24 welded to the cylindrical side wall of the housing. A gasket is provided between the two parts fitted together.

It will be observed in Figure 1 that the transverse cross-sectional area of the filter somewhat exceeds the transverse cross-sectional area of the downstream pipework 20. It will be appreciated that if a filter were to be fitted into the downstream pipework itself, this filter could only be fairly small. It will be appreciated therefore that provision of the filter unit, comprising a housing and a filter, removes constraints on filter size, so that a much larger filter can be employed, which gives more efficient operation, and needs to be removed less frequently for disposal of retained solids and for cleaning. Thus, in this embodiment, the downstream pipework is about 40 mm in diameter, and the filter is about 50 mm in diameter. The filter is about 200 mm long.

It will be appreciated that the filter simply rests on the seating provided at the drainage outlet of the bowl urinal 8, and the filter may be lifted out, when required.

When the filter is empty, liquid may flow to the downstream pipework via the apertures 12 in the flange, and via the perforate wall of the filter, including the lower wall 14. If the filter is half full of solid materials, liquid can flow through the apertures 12 and through the upper half of the perforate side wall of the filter. When the filter is completely full, liquid can only effectively filter through the apertures 12, and it will be apparent from visual inspection that the filter needs to be removed, for emptying and cleaning.

The filter and the housing are both of a highly polished stainless steel material. The annular flange 10 and the side wall of the filter 2 are highly polished, and preferably of a mirror finish. The mirror finish may prevent build up of alkaline and/or uric acid in the filter.

The embodiment of Figure 3 is similar to that of Figure 1, the main difference being in the upper region of the filter. The filter rests on seating provided by an upper wall of the housing. The upper wall is secured to the side wall of the cylindrical housing, by means of bolts/nuts, in similar matter to the bottom wall of the housing.

In the embodiment of Figure 4, the filter unit is beneath the outlet of a sink 30, and the filter comprises a cylindrical body which is secured at its upper end to an annular plastics body 32. A plug 34 of similar material is provided for location within the annular body, over the mouth of the filter. The annular plastics body 32 does not have any apertures, and in this respect differs from the embodiments described hereinabove. The plug 34 preferably has a diameter of around four to five inches.

A filter 40 shown in Figures 5 and 6 is similar to the filter 2 described previously. The filter 40, however, has a wider flange than that described previously. For example, the flange 42 of Figure 6 has a width of about 40% of the diameter of cylindrical region 44. Additionally the flange 42 carries three positioning pins 46 on a lower surface and furthermore has a cut out region 48 so as to allow the flange to fit around a hinge heel of a known dome strainer. The cylindrical region 44 of the filter 40 is formed from a sheet of perforated material. Opposite ends of the sheet are butted together and welded at spaced apart locations 50.

The filter 40 may be used in a channel basin 52, having a waste down pipe 54, as shown in Figure 7. The filter is pushed into the pipe 54 so that the flange 42 of the filter abuts a flange 56 of the down pipe 54. The filter 40 is automatically positioned axially within the pipe 54 due to the provision of the three pins 46 which abut, or are closely adjacent to, the flange 56 of the down pipe. The provision of pins 46 restricts transverse movement of the filter 40 relative to the down pipe 54.

Instead of positioning pins 46, the flange 42 of the filter 40 may include a plurality of punched holes. The punching of the upper surface of the flange may result in the production of burred edges projecting below the flange which may serve the same purpose as the pins 46 described.

The down pipe 54 of Figure 7 may have a diameter of about 1i to 2i inches (3.8 to 6.4 cm), and the filter unit then being dimensioned to fit such a pipe.

Whilst the embodiments hereinabove described have a filter made of stainless steel, the invention also includes embodiments in which the filter is made of, or has a surface coated with, a material which is resistant to build up of deposits of chemicals, such as uric acid, which may be dissolved in the liquid.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (24)

1. A filter for location beneath a drainage outlet, the filter comprising a hollow filter body which includes a filter surface, wherein a first end of the filter is arranged to be located beneath the drainage outlet, the filter including a mouth open to the first end which mouth is arranged, in use, to allow liquid to pass from the drainage outlet and into the hollow body so that the liquid may be filtered by the filter surface.

2. A filter according to Claim 1, wherein the filter has a flange at the first end, about the mouth.

3. A filter according to Claim 2, wherein the flange has a plurality of apertures, so that liquid may pass through the apertures, as well as through the filter surface of said filter body.

4. A filter according to any of the preceding claims, wherein the filter is arranged to be fitted in a waste down pipe beneath a drainage outlet.

5. A filter according to any of the preceding claims, wherein the filter includes positioning means for positioning the filter in a waste down pipe.

6. A filter according to Claim 5, wherein the positioning means is arranged such that, with the filter fitted in a waste down pipe, there is a gap defined between the outer periphery of the hollow filter body and the down pipe.

7. A filter according to Claim 2 in combination with Claim 5 or Claim 6, wherein the positioning means comprises a projecting part or parts on said flange.

8. A filter according to Claim 7, wherein the projecting part or parts is/are arranged to restrict transverse movement of the filter, in use.

9. A filter according to Claim 7 or Claim 8, wherein the projecting part or parts is/are provided on a surface of the flange which surface is a lowermost surface in use.

10. A filter according to any of Claims 7 to 9, wherein the projecting part(s) is/are in the form of one or a plurality of pins.

11. A filter according to any of Claims 7 to 9, wherein the projecting part(s) comprise burred edges of one or a plurality of holes punched (or otherwise formed) in the flange.

12. A filter according to any of the preceding claims, wherein the diameter of the filter body is in the range 35mm to 90mm.

13. A filter according to any of the preceding claims wherein the filter body has a diameter of less than 50mm.

14. A filter according to any of the preceding claims, wherein the filter is elongate.

15. A filter according to any of the preceding claims, wherein the filter surface extends from the mouth of the filter towards a second end of the filter.

16. A filter according to any of the preceding claims, wherein liquid may flow through the filter body at any position beneath the first end.

17. A filter according to any of the preceding claims, wherein a surface of the filter is highly polished and/or has a mirror finish.

18. A filter according to any of the preceding claims, wherein the filter is coated with a material which is resistant to build up of chemical deposits.

19. An assembly comprising a filter according to any of Claims 1 to 18, the filter being secured in a down pipe beneath a drainage outlet.

20. Use of a filter according to any of Claims 1 to 18 for filtering liquid passing from a drainage outlet of a fitting, for example a urinal, sink, basin or mortuary table.

21. A filter unit for location beneath a drainage outlet, the unit comprising a first end for location adjacent a said drainage outlet, and a second end for connection to downstream pipework, the unit comprising a filter as described in any of Claim 1 to 18, wherein the filter has its mouth open to the first end, the unit further comprising a housing within which the filter is received, with a gap being defined between the housing and the filter, the housing having an outlet at the second end, for connection to downstream pipework.

22. A filter unit according to Claim 20, wherein the housing is of complimentary shape to the filter.

23. A filter unit according to Claim 21 or Claim 22, wherein the housing is adapted for securement about a said drainage outlet.

24. A filter unit according to any of Claim 21 to 23, wherein a wall of the housing at the second end (the bottom wall in use) is removable to aid the securement of downstream pipework.